This invention relates to wiping devices for metal strip, particularly those using three small diameter metal rollers to wipe surplus coolant from the surfaces of strip emerging from a rolling mill, when each metal roller is supported by a plurality of pairs of support rollers, such as those disclosed in our U.S. Pat. No. 4,551,878.
We have found that this method of wiping the strip has been very successful, and there are now several installations in operation. However, it has been established that when the strip tension is very low, which occurs when very light gauge strip is being rolled, this three roller wiping arrangement becomes inefficient because the tension is insufficient to generate high pressure between wiper rollers and the strip. The result of this is that the strip wraps around each roller, and a hydrodynamic oil film develops between each roller and the strip. This film remains on the strip as the strip leaves the strip wiper, thus greatly diminishing the effectiveness of the wiping action.
The present invention overcomes this deficiency, in one embodiment, by providing for the removal of the two upper wiper rollers, together with their bearings and chocks, and replacing them with a single upper wiper roller, mounted vertically in line with the existing lower wiper roller. The invention also includes splash prevention means to prevent oil from splashing over the top of the upper wiper roller.
In another embodiment, for wiping light gauge strip only, the present invention consists of a 2-roller wiper arrangement, with a single upper wiper roller mounted vertically in line with a single lower wiper roller.
In yet another embodiment two set of support bearings are provided at the bottom, enabling either a single roller to be located centrally to provide a three roller wiping mode, or two rollers to be provided at the bottom vertically in line with the two upper rollers, thus providing two separate pairs of two roller wipers within the structure, i.e. a double two roller wiper arrangement.